Is it illegal to use a WiFi jammer? Why?

In many countries, it is illegal to sell and use WiFi signal jammers, mainly because of what?

Topsignaljammer  2022.3

We can look at the laws on radio in one of the following countries:
According to Article 70 of the "Radio Administration Regulations", whoever violates the provisions of these Regulations, uses radio frequencies without permission, or sets up and uses radio stations (stations) without authorization, the radio administration agency shall order corrections and confiscate the equipment engaged in illegal activities and illegal gains, a fine of not more than 50,000 yuan may be imposed concurrently; if refusal to make corrections, a fine of not less than 50,000 yuan but not more than 200,000 yuan may be imposed concurrently.
The "Criminal Law" also stipulates that, in violation of state regulations, setting up or using radio stations (stations) without authorization, interfering with the normal operation of radio communications, and causing serious consequences, shall be sentenced to fixed-term imprisonment of not more than three years, criminal detention or public surveillance, and shall also or only be fined.

It can be seen from this that in many countries, the use of wifi jammer will interfere with the communication of others and hinder the freedom of communication of others, which is illegal.